Autonomous robots that perform household functions such as floor cleaning and lawn cutting are now readily available consumer products. Some robots are generally confined within (i) touched walls and other obstacles within the rooms of a dwelling, (ii) IR-detected staircases (cliffs) leading downward; and/or (iii) user-placed detectable barriers such as directed IR beams, physical barriers or magnetic tape. Walls often provide much of the confinement perimeter. Other robots may try to map the dwelling using a complex system of sensors and/or active or passive beacons (e.g., sonar, RFID or bar code detection, or various kinds of machine vision).
Some autonomous robotic lawn mowers use a continuous boundary marker (e.g., a boundary wire) for confining random motion robotic mowers. The boundary wire is intended to confine the robot within the lawn or other appropriate area, so as to avoid damaging non-grassy areas of the yard or intruding onto a neighboring property. The boundary wire is typically a continuous electrically conductive loop around the property to be mowed. Although the boundary wire can be drawn into the property in peninsulas to surround gardens or other off-limit areas, it remains a continuous loop, and is energized with an AC current detectable as a magnetic field at a distance of a few feet. The boundary wire loop must be supplied with power, usually from a wall socket. Within the bounded area, a mowing robot may “bounce” randomly as the robot nears the guide conductor, or may follow along the guide conductor. Some mowers also touch and bounce from physical barriers.